U.S. patent number 9,859,737 [Application Number 15/084,488] was granted by the patent office on 2018-01-02 for method and apparatus for performing system power management in electronic device equipped with battery.
This patent grant is currently assigned to MediaTek Inc.. The grantee listed for this patent is MEDIATEK INC.. Invention is credited to Pi-Fen Chen, Chih-Yuan Hsu, Hung-I Wang.
United States Patent |
9,859,737 |
Chen , et al. |
January 2, 2018 |
Method and apparatus for performing system power management in
electronic device equipped with battery
Abstract
A method and an apparatus for performing charging port detection
control are provided, where the method is applied to an electronic
device, a communication port of the electronic device has a
functionality of obtaining power from an external power source for
the electronic device, and a power path switching unit of the
electronic device is arranged to control electrical connection
between a system within the electronic device and a battery of the
electronic device. The method may include the steps of: performing
charging port detection; and control operation(s) according to the
charging port detection. For example, the method may include:
controlling the power path switching unit to have different
configuration according to the charging port detection in order to
charge the battery with different charging profiles; and detecting
the system voltage level during charging for switching from the
constant current mode to the constant voltage mode.
Inventors: |
Chen; Pi-Fen (Hsinchu County,
TW), Hsu; Chih-Yuan (Hsinchu, TW), Wang;
Hung-I (Hsinchu County, TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
MEDIATEK INC. |
Hsin-Chu |
N/A |
TW |
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Assignee: |
MediaTek Inc. (Hsin-Chu,
TW)
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Family
ID: |
48222867 |
Appl.
No.: |
15/084,488 |
Filed: |
March 30, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160211691 A1 |
Jul 21, 2016 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13610909 |
Sep 12, 2012 |
9327321 |
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61557551 |
Nov 9, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J
7/0068 (20130101); B65D 19/385 (20130101); H02J
7/007184 (20200101); H02J 7/00034 (20200101); B08B
3/022 (20130101); F26B 3/0923 (20130101); F26B
3/08 (20130101); B08B 13/00 (20130101) |
Current International
Class: |
H02J
7/00 (20060101); B08B 3/02 (20060101); B08B
13/00 (20060101); F26B 3/08 (20060101); F26B
3/092 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1741345 |
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Mar 2006 |
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CN |
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101478171 |
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Dec 2010 |
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CN |
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101989749 |
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Mar 2014 |
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CN |
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200740005 |
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Oct 2007 |
|
TW |
|
201030512 |
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Aug 2010 |
|
TW |
|
Primary Examiner: Levin; Naum B
Attorney, Agent or Firm: Wolf, Greenfield & Sacks,
P.C.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a divisional application of U.S.
Non-provisional application Ser. No. 13/610,909, now U.S. Pat. No.
9,327,321 B2, which was filed on Sep. 12, 2012 and is included
herein by reference. The U.S. Non-provisional application Ser. No.
13/610,909 claims the benefit of U.S. Provisional Application No.
61/557,551, which was filed on Nov. 9, 2011.
Claims
What is claimed is:
1. A method for performing system power management, the method
being applied to an electronic device, the method comprising the
steps of: performing charging port detection on a communication
port of the electronic device, wherein the communication port
obtains power from an external power source for the electronic
device; determining a charging capability of the external power
source from a first charging capability and a second charging
capability, the second charging capability being weaker than the
first charging capability; when it is detected that the external
power source has the second charging capability, waiting to turn on
a system within the electronic device until a voltage level of a
battery of the electronic device reaches a predetermined voltage
level; controlling a power path switching unit of the electronic
device to charge the battery of the electronic device and detecting
whether a voltage level of a system power at a system terminal
coupling the system within the electronic device reaches a
predetermined threshold value in a constant current mode during
charging the battery, wherein the power path switching unit is
arranged to control electrical connection between the system and
the battery, and a charging current level in the constant current
mode is determined according to the charging capability of the
external power source; and when it is detected that the voltage
level reaches the predetermined threshold value in the constant
current mode during charging the battery, switching from the
constant current mode to a constant voltage mode, wherein in a
charging phase starting from a time point of switching from the
constant current mode to the constant voltage mode, the voltage
level is kept at a true constant voltage.
2. The method of claim 1, wherein the step of performing the
charging port detection on the communication port further
comprises: determining whether the external power source belongs to
a predetermined type of power sources; wherein the power path
switching unit is controlled according to whether the external
power source belongs to the predetermined type of power
sources.
3. The method of claim 2, wherein the step of controlling the power
path switching unit further comprises: when it is detected that the
external power source belongs to the predetermined type of power
sources, turning on the power path switching unit to charge the
battery in accordance with a predetermined charging profile
corresponding to the predetermined type.
4. The method of claim 1, wherein at a moment of switching from the
constant current mode to the constant voltage mode, the system
power is arranged to charge the battery and to power the system
simultaneously.
5. The method of claim 1, further comprising: regulating the
voltage level of the system power during the constant voltage
mode.
6. The method of claim 1, wherein the step of determining a
charging capability of the external power source comprises
determining a current level that the external power source is
capable of providing.
7. An apparatus for performing system power management, the
apparatus comprising at least one portion of an electronic device,
the apparatus comprising: a charging port detection circuit
arranged to perform charging port detection on a communication port
of the electronic device, wherein the communication port obtains
power from an external power source for the electronic device, and
determine a charging capability of the external power source from a
first charging capability and a second charging capability, the
second charging capability being weaker than the first charging
capability; and a charger module, electrically connected to the
charging port detection circuit, wherein: when it is detected that
the external power source has the second charging capability, the
charger module waits to turn on a system within the electronic
device until a voltage level of a battery of the electronic device
reaches a predetermined voltage level, the charger module controls
a power path switching unit of the electronic device to charge the
battery of the electronic device, and the charger module detects
whether a voltage level of a system power at a system terminal
coupling the system within the electronic device reaches a
predetermined threshold value in a constant current mode during
charging the battery, wherein: the power path switching unit is
arranged to control electrical connection between the system and
the battery, a charging current level in the constant current mode
is determined according to the charging capability of the external
power source, and when it is detected that the voltage level
reaches the predetermined threshold value in the constant current
mode during charging the battery, the charger module switches from
the constant current mode to a constant voltage mode, wherein in a
charging phase starting from a time point of switching from the
constant current mode to the constant voltage mode, the voltage
level is kept at a true constant voltage.
8. The apparatus of claim 7, wherein the charging port detection
circuit determines whether the external power source belongs to a
predetermined type of power sources; and the charger module
controls the power path switching unit according to whether the
external power source belongs to the predetermined type of power
sources.
9. The apparatus of claim 8, wherein when it is detected that the
external power source belongs to the predetermined type of power
sources, the charger module turns on the power path switching unit
to charge the battery in accordance with a predetermined charging
profile corresponding to the predetermined type.
10. The apparatus of claim 7, wherein at a moment of switching from
the constant current mode to the constant voltage mode, the system
power is arranged to charge the battery and to power the system
simultaneously.
11. The apparatus of claim 7, wherein the charger module further
regulates the voltage level of the system power during the constant
voltage mode.
12. The apparatus of claim 7, wherein the charger module comprises:
a controller arranged to control operations of the charger module;
and a regulator arranged to generate the system power signal under
control of the controller; wherein the apparatus further comprises:
a monitoring circuit arranged to monitor the voltage level of the
system power under control of the controller.
13. The apparatus of claim 7, wherein the charging port detection
circuit is arranged to determine a current level that the external
power source is capable of providing.
Description
BACKGROUND
The present invention relates to a charger module within an
electronic device, and more particularly, to a method for
performing system power management, and to an associated
apparatus.
A portable electronic device equipped with batteries (e.g., a
multifunctional mobile phone, a personal digital assistant (PDA), a
tablet, etc) can be very convenient to a user. According to the
related art, the portable electronic device may be designed to have
a Universal Serial Bus (USB) port, and the user can electrically
connect the portable electronic device to an electronic device
complying with USB standards through the USB port when needed, or
charge the portable electronic device (more particularly, the
battery thereof) with a power source temporarily connected to the
USB port, where the power source can be a USB charger, or can be a
personal computer (PC) since the USB port of the portable
electronic device can obtain power from the power source through
the USB port. Based upon the conventional power management methods
in the related art, in a situation where the system power
consumption of the portable electronic device is increased due to
design changes (e.g., enhanced hardware speed/performance and the
enlarged screen size), some problems may occur. For example,
switching the system power input of the portable electronic device
according to the related art allows the user to use the portable
electronic device when the battery is deeply discharged or even the
battery is absent. Furthermore, the system power may be perturbed
during the power source switching. In another example, the portable
electronic device may suffer from deficient/unstable power when the
portable electronic device is merely powered by a USB-complaint
standard downstream port or a USB On-The-Go (OTG) device without
using the battery. Thus, a novel method is required for enhancing
system power management of an electronic device.
SUMMARY
It is therefore an objective of the claimed invention to provide a
method for performing system power management, and to provide an
associated apparatus, in order to solve the above-mentioned
problems.
An exemplary embodiment of a method for performing system power
management is provided, where the method is applied to an
electronic device, a communication port of the electronic device
has a functionality of obtaining power from an external power
source for the electronic device, and a power path switching unit
of the electronic device is arranged to control electrical
connection between a system within the electronic device and a
battery of the electronic device. The method comprises the steps
of: performing charging port detection on the communication port;
controlling the power path switching unit to charge the battery and
detecting whether a voltage level of a system power signal at a
power input terminal of the system reaches a predetermined
threshold value in a constant current mode during charging the
battery; and when it is detected that the voltage level reaches the
predetermined threshold value in the constant current mode during
charging the battery, switching from the constant current mode to a
constant voltage mode.
An exemplary embodiment of an apparatus for performing system power
management is provided, where the apparatus comprises at least one
portion of an electronic device, a communication port of the
electronic device has a functionality of obtaining power from an
external power source for the electronic device, and a power path
switching unit of the electronic device is arranged to control
electrical connection between a system within the electronic device
and a battery of the electronic device. The apparatus comprises a
charging port detection circuit, and further comprises a charger
module, electrically connected to the charging port detection
circuit. The charging port detection circuit is arranged to perform
charging port detection on the communication port. In addition, the
charger module controls the power path switching unit to charge the
battery and detects whether a voltage level of a system power at a
power input terminal of the system reaches a predetermined
threshold value in a constant current mode during charging the
battery. When it is detected that the voltage level reaches the
predetermined threshold value in the constant current mode during
charging the battery, the charger module switches from the constant
current mode to a constant voltage mode.
An exemplary embodiment of a method for performing system power
management is provided, where the method is applied to an
electronic device, a communication port of the electronic device
has a functionality of obtaining power from an external power
source for the electronic device, and a power path switching unit
of the electronic device is arranged to control electrical
connection between a system within the electronic device and a
battery of the electronic device. The method comprises the steps
of: performing charging port detection on the communication port to
determine whether the external power source belongs to a
predetermined type of power sources; and when it is detected that
the external power source belongs to the predetermined type of
power sources, controlling the power path switching unit to make
the output voltage of the battery or the system power to meet a
first charging profile.
An exemplary embodiment of an apparatus for performing system power
management is provided, where the apparatus comprises at least one
portion of an electronic device, a communication port of the
electronic device has a functionality of obtaining power from an
external power source for the electronic device, and a power path
switching unit of the electronic device is arranged to control
electrical connection between a system within the electronic device
and a battery of the electronic device. The apparatus comprises a
charging port detection circuit, and further comprises a charger
module, electrically connected to the charging port detection
circuit. The charging port detection circuit is arranged to perform
charging port detection on the communication port to determine
whether the external power source belongs to a predetermined type
of power sources. In addition, when it is detected that the
external power source belongs to the predetermined type of power
sources, the charger module controls the power path switching unit
to make the output voltage of the battery or the system power to
meet a first charging profile.
These and other objectives of the present invention will no doubt
become obvious to those of ordinary skill in the art after reading
the following detailed description of the preferred embodiment that
is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram of an apparatus for performing system power
management according to a first embodiment of the present
invention.
FIG. 2 illustrates a flowchart of a method for performing system
power management according to an embodiment of the present
invention.
FIG. 3 illustrates a flowchart of a method for performing Step 240
shown in FIG. 2 according to an embodiment of the present
invention.
FIG. 4 illustrates a flowchart of a method for performing Step 250
shown in FIG. 2 according to an embodiment of the present
invention.
FIG. 5 illustrates a predetermined charging profile involved with
the method shown in FIG. 2 and FIG. 4 according to an embodiment of
the present invention.
FIG. 6 illustrates a predetermined charging profile involved with
the method shown in FIG. 2 according to another embodiment of the
present invention.
FIG. 7 illustrates a predetermined charging profile involved with
the method shown in FIG. 2 and FIG. 3 according to an embodiment of
the present invention.
FIG. 8 illustrates a predetermined charging profile involved with
the method shown in FIG. 2 according to another embodiment of the
present invention.
DETAILED DESCRIPTION
Certain terms are used throughout the following description and
claims, which refer to particular components. As one skilled in the
art will appreciate, electronic equipment manufacturers may refer
to a component by different names. This document does not intend to
distinguish between components that differ in name but not in
function. In the following description and in the claims, the terms
"include" and "comprise" are used in an open-ended fashion, and
thus should be interpreted to mean "include, but not limited to . .
. ". Also, the term "couple" is intended to mean either an indirect
or direct electrical connection. Accordingly, if one device is
coupled to another device, that connection may be through a direct
electrical connection, or through an indirect electrical connection
via other devices and connections.
Please refer to FIG. 1, which illustrates a diagram of an apparatus
100 for performing system power management according to a first
embodiment of the present invention. According to different
embodiments, such as the first embodiment and some variations
thereof, the apparatus 100 may comprise at least one portion (e.g.
a portion or all) of an electronic device. For example, the
apparatus 100 may comprise a portion of the electronic device
mentioned above, and more particularly, can be a control circuit
such as an integrated circuit (IC) within the electronic device. In
another example, the apparatus 100 can be the whole of the
electronic device mentioned above. In another example, the
apparatus 100 can be an audio/video system comprising the
electronic device mentioned above. Examples of the electronic
device may include, but not limited to, a mobile phone (e.g. a
multifunctional mobile phone), a personal digital assistant (PDA),
a portable electronic device such as a tablet, and a personal
computer such as a laptop computer or desktop computer.
According to the embodiment shown in FIG. 1, a communication port
of the electronic device has a functionality of obtaining power
from an external power source for the electronic device, where the
communication port typically comprises at least one power terminal
regarding the functionality of obtaining power from the external
power source for the electronic device. For example, the
communication port can be a Universal Serial Bus (USB) port whose
connector, such as a USB connector (not shown), may comprise a
plurality of terminals VBUS, D-, D+ and GND, where the terminal
VBUS can be regarded as the aforementioned at least one power
terminal, the terminals D- and D+ can be regarded as data terminals
(or communication terminals) of the aforementioned communication
port such as the USB port, and the terminal GND can be regarded as
a ground terminal. According to this embodiment, the data terminals
DP and DN shown in FIG. 1 can be electrically connected to the data
terminals D+ and D- of the USB connector, respectively, and
therefore can be regarded as the data terminals D+ and D- of the
USB connector in this situation, respectively. As shown in FIG. 1,
the apparatus 100 comprises a charging port detection circuit 110,
a monitoring circuit 120, and a charger module 130. For example,
the monitoring circuit 120 of this embodiment may comprise a
multiplexer 122 and a comparator 124 (labeled "MUX" and "CMP",
respectively, for brevity), and the charger module 130 of this
embodiment may comprise a controller 132, a pulse width modulator
134 (labeled "PWM", for brevity), and an inductor L. This is the
switching type example. The charger module is not limited to be
switching type. It can be linear or pulsed type, too.
In this embodiment, the charging port detection circuit 110 is
arranged to perform charging port detection, and the monitoring
circuit 120 is arranged to selectively monitor the voltage level
VSYS of the system power from the system terminal SYS of the
charger module 130 or monitor the battery voltage level on the
battery terminal BAT of the battery 20. Please note that monitoring
the voltage level VSYS or monitoring the voltage level VBAT forms a
voltage regulation loop. The current information flowing into the
battery 20 or output from the charger module can also feedback to
the comparator 124 via the multiplexer 122 to form a current
regulation loop, which is not shown in FIG. 1 for simplification.
The monitoring circuit 120 shown in FIG. 1 is for illustrative only
and not a limitation. Please further note that monitoring the
voltage level VSYS and monitoring the voltage level VBAT are
different things since the power path between the system terminal
SYS and the battery terminal BAT may be selectively disabled, where
some details regarding the power path will be described later. For
example, the monitoring circuit 120 may be arranged to selectively
monitor the voltage level VSYS. For example, the monitoring circuit
120 may be arranged to selectively monitor the voltage level VBAT.
More particularly, under control of the controller 132, the
multiplexer 122 is capable of multiplexing one of the voltage level
VSYS on the system terminal SYS and the output voltage level VBAT
on the battery terminal BAT, for being input into the comparator
124. When utilizing the multiplexer 122 to select one of the
voltage level VSYS and the output voltage level VBAT, the
monitoring circuit 120 can monitor the selected voltage level (e.g.
the voltage level VSYS or the output voltage level VBAT) by
utilizing the comparator 124 to compare the selected voltage level
(e.g. the voltage level VSYS or the output voltage level VBAT) with
a predetermined reference voltage level Vref, where under control
of the controller 132, the monitoring circuit 120 can select the
predetermined reference voltage level Vref from a set of
predetermined reference voltage levels {Vref} when needed. In
addition, the charger module 130 is capable of providing power to
the system terminal SYS coupling to a system circuit (not shown in
the figure) within the electronic device and charging at least one
battery of the electronic device, such as the battery 20 shown in
FIG. 1, where the system circuit mentioned above can be referred to
as the system, for brevity.
Please note that the combination of the pulse width modulator 134
and the inductor L can be regarded as a regulator that is capable
of determining the voltage level VSYS of the system power output
from the system terminal SYS of the charger module 130 under
control of the controller 132. According to this embodiment, the
controller 132 is arranged to control operations of the charger
module 130, such as the pulse width modulation performed by the
pulse width modulator 134. The pulse width modulator 134 is capable
of outputting a pulse width modulated signal having a specific duty
cycle at the terminal LX, where the voltage level VSYS corresponds
to the specific duty cycle, and the specific duty cycle is
determined by the controller 132. Thus, the charger module 130 is
capable of regulating the input received from the charger input
terminal CHRIN, which is for example electrically connected to the
power terminal VBUS of the USB connector mentioned above. For
example, in a situation where the external power source is a USB
charger such as an alternating current (AC)-to-direct current (DC)
adaptor having a USB cable for outputting power, the output power
of the AC-to-DC adaptor is received through the power terminal VBUS
and is input into the charger module 130 through the charger input
terminal CHRIN. In another example, in a situation where the
external power source is a personal computer (PC) with a USB cable
being temporarily connected between the PC and the electronic
device, the output power of the PC is received through the power
terminal VBUS and is input into the charger module 130 through the
charger input terminal CHRIN.
As shown in FIG. 1, a power path switching unit P_SW is installed
on the power path between the system terminal SYS of the charger
module 130 and the battery terminal BAT of the battery 20, where
the power path switching unit P_SW of the electronic device is
arranged to control electrical connection between the system within
the electronic device and the battery 20 of the electronic device.
Typically, the system is electrically connected to the system
terminal SYS, for selectively being powered by the charger module
130 or the battery 20 with the aid of the power path switching unit
P_SW controlled by the controller 132. According to this
embodiment, in a situation where the controller 132 turns on (i.e.
close) the power path switching unit P_SW to enable the
aforementioned power path, the charger module 130 is capable of
charging the battery 20. This is for illustrative purposes only,
and is not meant to be a limitation of the present invention. The
apparatus 100 can enable the power path to perform other
operations. For example, in a situation where the controller 132
turns on the power path switching unit P_SW to enable the
aforementioned power path, the system can be powered by the battery
20. In addition, in a situation where the controller 132 turns off
(i.e. open) the power path switching unit P_SW to disable the
aforementioned power path, the charger module 130 is capable of
providing the system with the system power directly when the
battery 20 is in a low battery condition. More particularly, when
the battery 20 is in the low battery condition, the controller 132
may turn off the power path switching unit P_SW to disconnect the
battery 20 from the system terminal SYS of the charger module 130,
in order to prevent the voltage level VSYS of the system power
output from the system terminal SYS from being pulled down by the
battery 20 in the low battery condition.
Typically, the charger module 130 may comply with Battery Charging
(BC) Specifications such as Revision 1.1 or Revision 1.2 thereof,
i.e. the so-called BC 1.1 or BC 1.2, for USB-compliant devices,
where at least one portion of the aforementioned BC 1.1 and BC 1.2
defines the mechanisms that allow devices to distinguish the type
of the USB port, and typically, it can be achieved by a detection
sequence on D+ and D- data lines (i.e. the data lines respectively
corresponding to the data terminals D+ and D-). For example,
regarding aforementioned charging port detection, the charging port
detection circuit 110 may comprise some hardware circuits for
generating the detection sequences.
Please refer to FIG. 2 in combination with FIG. 1. FIG. 2
illustrates a working flow of a method 200 for performing system
power management according to an embodiment of the present
invention. The method shown in FIG. 2 can be applied to the
apparatus 100 shown in FIG. 1. The method is described as
follows.
In Step 210, the charger module 130 (more particularly, the
controller 132) detects whether there is a valid charger
electrically connected to the USB connector mentioned above. In
practice, the controller 132 is capable of detecting the input
received from the charger input terminal CHRIN by using a detection
circuit therein (not shown), where the detection circuit can be a
comparator arranged to detect a voltage variation (or a voltage
increment) of the input received from the charger input terminal
CHRIN. For example, in a situation where an external power source
is electrically connected to the USB connector, the controller 132
may detect the existence of the external power source by using this
detection circuit. In another example, in a situation where a first
end of a USB cable is plugged into the USB connector with the other
end of this USB cable being unplugged, the controller 132 will not
detect a valid charger. When it is detected that there is a valid
charger electrically connected to the USB connector, Step 220 is
entered; otherwise, Step 210 is re-entered.
In Step 220, the charging port detection circuit 120 performs the
aforementioned charging port detection, where the BC 1.1 or BC 1.2
charging port detection can be taken as an example of the charging
port detection.
In Step 230, based upon the detection result of the charging port
detection mentioned in Step 220, the controller 132 determines
whether the external power source is a predetermined type power
source (more particularly, determines whether the external power
source belongs to a predetermined type of power sources). In one
embodiment, the determination is made according to the charging
capability that the external power source can provide, such as a
current level that the external power source is capable of
providing. When it is detected that the external power source has a
weak charging capability (more particularly, an insufficient
current rating, for example, in a situation where the system
circuit needs an input current level that is greater than 500
milliampere (mA) to sustain the system load and the external power
source is a USB-complaint standard downstream port or a USB
On-The-Go (OTG) device), Step 240 is entered; otherwise, the
external power source has a strong charging capability (more
particularly, a sufficient current rating, for example, in a
situation where the system circuit needs an input current level
that is greater than 500 mA to sustain the system load and the
external power source is an AC-to-DC adaptor or a USB device other
than the above-mentioned USB-complaint standard downstream port or
USB OTG device), Step 250 is entered. Please note that since a
skilled person should easily understand how to accomplish the
above-mentioned charging port detection (or charger type
detection), the detailed description is omitted for brevity.
In Step 240, the power path switching unit P_SW is controlled to
have a first configuration such that the charger module 130 charges
the battery 20 according to a first charging profile (e.g. one of
the predetermined charging profiles respectively shown in FIG. 7
and FIG. 8). As a result, the I-V curve (i.e. the relationship of
the charging current and the output voltage) of the battery 20 or
the system power meets the first charging profile.
In Step 250, the power path switching unit P_SW is controlled to
have a second configuration such that the charger module 130
charges the battery 20 according to a second charging profile (e.g.
one of the predetermined charging profiles respectively shown in
FIG. 5 and FIG. 6). As a result, the I-V curve (i.e. the
relationship of the charging current and the output voltage) of the
battery 20 or the system power meets the second charging
profile.
FIG. 3 illustrates a flowchart of Step 240 shown in FIG. 2
according to an embodiment of the present invention. Since the
external power source may not be capable of providing sufficient
current (for example, the maximum current that the USB-complaint
standard downstream port and the USB OTG device can provide is 500
mA and 100 mA, respectively) to sustain the operation of the system
of the electronic device, it may cause instability of the system if
the system is powered by the external power source solely without
the aid of the battery. Therefore, the charging profile proposed in
this embodiment first charges the battery without turning on the
system when the battery voltage VBAT is low, and allows the system
to be enabled when the battery voltage VBAT is high enough. The
power received from the charger input terminal CHRIN then supplies
the system and charges the battery simultaneously. The method is
described as follows.
In Step 242, the charger module 130 (more particularly, the
controller 132) turns on the power path switching unit P_SW to
charge the battery 20 with the power received from the charger
input terminal CHRIN when the battery voltage VBAT is low.
Meanwhile, the system voltage VSYS is temporarily regulated to be
within a predetermined voltage range (e.g. to be less than 3.2 V)
to prevent the system from being turned on during this initial
phase of charging the battery 20. When the battery voltage VBAT is
high enough (e.g. reaches 3.2V), the system turns on, and the
output of the regulator (e.g. the system power signal) is utilized
to charge the battery 20 and to power the system simultaneously. In
this way, even the system requires a large current which is over
the maximum current that the weak external power source can
provide, the apparatus 100 can enter a battery supplement mode to
prevent the system from being shut down abruptly and keep the
operations stable.
The charger module 130 (more particularly, the controller 132) may
detect whether the output voltage level VBAT of the battery 20 is
low (i.e. less than a predetermined threshold value) with the aid
of the monitoring circuit 120. When it is detected that the
external power source belongs to the predetermined type of power
sources and that the output voltage level of the battery is less
than the predetermined threshold value, the charger module 130
(more particularly, the controller 132) controls the power path
switching unit P_SW to charge the battery 20. The power path
switching unit P_SW may be implemented by transistors, and the
controller 132 may fully or partially turns on the transistors of
the power path switching unit P_SW to charge the battery 20. For
example, the system voltage VSYS may be given a predetermined
voltage level (e.g. 2.5V) which is less than the power-on voltage
of the system by the charger module 130, and the partially
turned-on transistors work as a low drop out (LDO) circuit to
provide current to the battery 20 by converting the system voltage
VSYS. Or, the fully turned-on transistors forma direct path that
connecting the system power terminal SYS to the battery output
terminal BAT, making the system voltage VSYS and the battery output
voltage VBAT rise uniformly when the battery 20 is charged by the
charger module 130.
The controller 132 may further controls the monitoring circuit 120
to detect whether the voltage level VSYS of the system power
reaches a predetermined threshold value Vth (e.g. 4.2 Volts (V)) in
the constant current mode during charging the battery 20 (Step
244). The multiplexer 122 of the monitoring circuit 120 may select
and pass the system voltage VSYS to the comparator 124.
In Step 246, when the comparator 124 detects that the voltage level
VSYS reaches the predetermined threshold value Vth (e.g. 4.2 V),
the charger module 130 switches from the constant current mode to
the constant voltage mode, and in Step 248, the charger module 130
regulates the voltage level VSYS to be at the predetermined
threshold value Vth during the constant voltage mode for preventing
the voltage level VSYS from exceeding the predetermined threshold
value Vth during charging the battery 20. The predetermined
threshold Vth represents a transition voltage level that the
charger module 130 switches from the constant current mode to the
constant voltage mode, and is generally depending on the battery
characteristics. According to this embodiment, at the moment of
switching from the constant current mode to the constant voltage
mode, the system power output from the system terminal SYS of the
charger module 130 is arranged to charge the battery 20 and to
power the system simultaneously since the power path switching unit
P_SW is turned on. In other words, the system power management
method proposed in this embodiment detects and regulates the system
voltage VSYS rather than the battery output voltage VBAT. As the
power path switching unit P_SW contributes a voltage drop on the
power path, the present method can effectively keep the power level
at the system power terminal SYS under a safe region, thereby
protecting the system coupled to the system power terminal SYS from
overshooting.
FIG. 4 illustrates a flowchart of Step 250 shown in FIG. 2
according to an embodiment of the present invention. Since the
external power source is capable of providing sufficient current to
sustain the operation of the system of the electronic device, it
can instantly enable the system and would not cause instability
without the aid of the battery. Therefore, the charging profile
proposed in this embodiment may power the system and charges the
battery at the same time. The method is described as follows.
In Step 252, when the external power source does not belong to the
predetermined type of power sources, the charger module 130 (more
particularly, the controller 132) is capable of controlling the
power path switching unit P_SW to make the electrical connection
between the system within the electronic device and the battery 20
of the electronic device to have a second configuration, where the
second configuration is typically different from the first
configuration. In one embodiment, the second configuration
corresponds to the conventional system instant-ON function and
power path management. Under this configuration, the charger module
130 may utilize the power received from the external power source
to power the system and charge the battery 20 simultaneously.
The controller 132 may further controls the monitoring circuit 120
to detect whether the voltage level VSYS of the system power signal
reaches a predetermined threshold value Vth (e.g. 4.2 V) in the
constant current mode during charging the battery 20 (Step 254).
The multiplexer 122 of the monitoring circuit 120 may select and
pass the system voltage VSYS to the comparator 124. In Step 256,
when the comparator 124 detects that the voltage level VSYS reaches
the predetermined threshold value Vth, the charger module 130
switches from the constant current mode to the constant voltage
mode, and in Step 258, the charger module 130 regulates the voltage
level VSYS to be at the predetermined threshold value Vth during
the constant voltage mode for preventing the voltage level VSYS
from exceeding the predetermined threshold value Vth during
charging the battery 20. The predetermined threshold Vth represents
a transition voltage level that the charger module 130 switches
from the constant current mode to the constant voltage mode, and is
generally depending on the battery characteristics. According to
this embodiment, at the moment of switching from the constant
current mode to the constant voltage mode, the system power signal
output from the system terminal SYS of the charger module 130 is
arranged to charge the battery 20 and to power the system
simultaneously since the power path switching unit P_SW is turned
on. In other words, the system power management method proposed in
this embodiment detects and regulates the system voltage VSYS
rather than the battery output voltage VBAT. As the power path
switching unit P_SW contributes a voltage drop on the power path,
the present method can effectively keep the power level at the
system power terminal SYS under a safe region, thereby protecting
the system coupled to the system power terminal SYS from
overshooting.
FIG. 5 illustrates a predetermined charging profile involved with
the method 200 shown in FIG. 2 and FIG. 4 according to an
embodiment of the present invention. FIG. 6 illustrates a
predetermined charging profile involved with the method 200 shown
in FIG. 2 according to another embodiment of the present invention.
In these embodiments, the notation Ich represents the charging
current output from the charger module 130, and the notations A
through to E represent different charging phases, respectively. For
better comprehension of the characteristics of the respective
partial curves of the charging phases A-E, the partial curves
corresponding to different charging phases (e.g. multiple charging
phases within the charging phases A-E) may be illustrated with
different scales.
According to any of the predetermined charging profiles
respectively shown in FIG. 5 and FIG. 6, the charger module 130 is
capable of charging the battery 20 by controlling the voltage level
VSYS and the charging current Ich. During the charging phase A, the
system voltage VSYS is given a predetermined initial voltage level
such as 3.7 V that is higher than the power-on voltage level
required by the system. Therefore the system is enabled. The
charger module 130 is capable of charging the battery 20 with a
predetermined initial current level such as 100 mA (e.g. the
charger module 130 controls the initial values of the voltage level
VSYS and the charging current Ich to be 3.7 V and 100 mA,
respectively) in a pre-charge mode to cause the output voltage
level VBAT reach a specific voltage level such as 2.5 V. Note that
the voltage/current levels given on the plot are for illustrative
purpose only. For example, the pre-charging current may be given
larger or smaller than 100 mA, and may not be fixed; it can be
varied according to the characteristics/requirements of the
battery. During the charging phase B, the charger module 130 is
capable of charging the battery 20 with a predetermined high
current level that is greater than the predetermined initial
current level in the pre-charge mode, where the charger module 130
may keep the system in its turn-on status while the output voltage
level VBAT is still relative low. During the charging phase C, the
charger module 130 is capable of charging the battery 20 with the
predetermined high current level in the constant current mode,
where the voltage level VSYS may go higher to cause the output
voltage level VBAT increase correspondingly, and the charger module
130 may keep the system in its turn-on status. During the charging
phase D, the charger module 130 may continue charging the battery
20 in the constant voltage mode while the charging current Ich is
decreasing, where the partial curves corresponding to the charging
phase D may be different in these embodiments. During the charging
phase E, the charging operation is completed, and the controller
132 can disable the power path by turning off the power path
switching unit P_SW, where the charger module 130 can supply the
system solely.
Regarding switching from the charging phase C to the charging phase
D in the embodiment shown in FIG. 5, the charger module 130 may
operate as mentioned in Step 254 to Step 258. When it is detected
that the voltage level VSYS reaches the predetermined threshold
value Vth (e.g. 4.2 V) in the constant current mode during charging
the battery 20, the charger module 130 switches from the constant
current mode to the constant voltage mode for preventing the
voltage level VSYS from exceeding the predetermined threshold value
Vth during charging the battery 20. Thus, the charger module 130
can regulate the voltage level VSYS (rather than the output voltage
level VBAT) to prevent the voltage level VSYS from overshooting. As
the charger module 130 regulates the voltage level VSYS at the
predetermined threshold value Vth during the charging phase D, the
diagram of FIG. 5 is labeled with the Regulate_VSYS mode.
Regarding switching from the charging phase C to the charging phase
D in the embodiment shown in FIG. 6, the charger module 130 may
operate as follows. When it is detected that the output voltage
level VBAT reaches the predetermined threshold value Vth (e.g. 4.2
V) in the constant current mode during charging the battery 20, the
charger module 130 switches from the constant current mode to the
constant voltage mode for preventing the output voltage level VBAT
from exceeding the predetermined threshold value Vth during
charging the battery 20. As the charger module 130 regulates the
output voltage level VBAT at the predetermined threshold value Vth
during the charging phase D, the diagram of FIG. 6 is labeled with
the Regulate_VBAT mode.
FIG. 7 illustrates a predetermined charging profile involved with
the method 200 shown in FIG. 2 and FIG. 3 according to an
embodiment of the present invention. FIG. 8 illustrates a
predetermined charging profile involved with the method 200 shown
in FIG. 2 according to another embodiment of the present invention.
Similarly, the notation Ich still represents the charging current
output from the charger module 130, and the notations A through to
E represent different charging phases, respectively. For better
comprehension of the characteristics of the respective partial
curves of the charging phases A-E, the partial curves corresponding
to different charging phases (e.g. multiple charging phases within
the charging phases A-E) may be illustrated with different
scales.
According to any of the predetermined charging profiles
respectively shown in FIG. 7 and FIG. 8, the charger module 130 is
capable of charging the battery 20 by controlling the voltage level
VSYS and the charging current Ich. During the charging phase A, the
voltage level VSYS is given a predetermined initial voltage level
such as 2.5 V that is less than the power-on voltage level required
by the system. Therefore, the system is not enabled. The charger
module 130 is capable of charging the battery 20 with a
predetermined initial current level such as 60 mA (e.g. the charger
module 130 controls the initial values of the voltage level VSYS
and the charging current Ich to be 2.5 V and 60 mA, respectively)
in a pre-charge mode to cause the output voltage level VBAT reach a
specific voltage level that is close to 2.5 V, where the system is
typically in its turn-off status. Please note that the notation
SYS_UVLO represents a power-on voltage level that is typically
defined by a designer of the system, where the power-on voltage
level SYS_UVLO can be regarded as a threshold for determining
whether the system can be turned on. For example, the power-on
voltage level SYS_UVLO may be defined to be 3.2 V. The
voltage/current levels given on the plot are for illustrative
purpose only. For example, the pre-charging current may be given
larger or smaller than 60 mA, and may not be fixed; it can be
varied according to the characteristics/requirements of the battery
while complying with the USB charging specifications. During the
charging phase C, the charger module 130 is capable of charging the
battery 20 with the predetermined initial current level before the
voltage level VSYS reaches the power-on voltage level SYS_UVLO.
During the charging phase C, when it is detected that the voltage
level VSYS reaches the power-on voltage level SYS_UVLO, the charger
module 130 is capable of switching the charging current Ich from
the predetermined initial current level to a predetermined high
current level that is greater than the predetermined initial
current level. During the charging phase D, the charger module 130
may continue charging the battery 20 while the charging current Ich
is decreasing, where the partial curves corresponding to the
charging phase D may be different in these embodiments. During the
charging phase E, the charging operation is completed, and the
controller 132 can disable the power path by turning off the power
path switching unit P_SW, where the charger module 130 can supply
the system solely.
Regarding switching from the charging phase C to the charging phase
D in the embodiment shown in FIG. 7, the charger module 130 may
operate as mentioned in Step 244 to Step 248. When it is detected
that the voltage level VSYS reaches the predetermined threshold
value Vth (e.g. 4.2 V) in the constant current mode during charging
the battery 20, the charger module 130 switches from the constant
current mode to the constant voltage mode for preventing the
voltage level VSYS from exceeding the predetermined threshold value
Vth during charging the battery 20. Thus, the charger module 130
can regulate the voltage level VSYS (rather than the output voltage
level VBAT) to prevent the voltage level VSYS from overshooting. As
the charger module 130 regulates the voltage level VSYS at the
predetermined threshold value Vth during the charging phase D, the
diagram of FIG. 7 is labeled with the Regulate_VSYS mode.
Regarding switching from the charging phase C to the charging phase
D in the embodiment shown in FIG. 8, the charger module 130 may
operate as follows. When it is detected that the output voltage
level VBAT reaches the predetermined threshold value Vth (e.g. 4.2
V) in the constant current mode during charging the battery 20, the
charger module 130 switches from the constant current mode to the
constant voltage mode, for preventing the output voltage level VBAT
from exceeding the predetermined threshold value Vth during
charging the battery 20. As the charger module 130 regulates the
output voltage level VBAT at the predetermined threshold value Vth
during the charging phase D, the diagram of FIG. 8 is labeled with
the Regulate_VBAT mode.
According to these embodiments, as the apparatus 100 can perform
the charging port detection as soon as the connector of the
external power source mentioned above is plugged into the USB
connector. For example, it can be detected through the data
terminals DP and DM, and in a situation where the charger module
130 complies with the USB BC 1.2 standard, the charging port
information can be used directly. In a situation where the external
power source mentioned above is a USB-complaint standard downstream
port or a USB OTG device (e.g. Step 240 is entered, based upon the
working flow of the method 200 shown in FIG. 2), the apparatus 100
can disable the system instant-on function. More particularly, when
the output voltage level VBAT is too low to sustain the system, the
controller 132 can always turn on the power path switching unit
P_SW, where the charger module 130 may focus on charging the
battery 20 during this period. As soon as the output voltage level
VBAT is high enough, the system can be turned on and the charger
module 130 can operate properly (more particularly, without
introducing any side effect) since the system load and the charging
current should not be a burden to the charger module 130 at this
moment. If the system load is heavy (e.g. the current drawn by the
system is greater than the input current limit), the voltage level
VSYS will just drop slightly because the apparatus 100 may enter
the battery supplement mode (in which both of the battery 20 and
the charger module 130 can be utilized for providing the system
with power) automatically and now the voltage level VBAT is high
enough. In a situation where the external power source mentioned
above is an AC-to-DC adaptor or a USB charger other than the
above-mentioned USB-complaint standard downstream port or USB OTG
device (e.g. Step 254 is entered, based upon the working flow of
the method 200 shown in FIG. 2), the apparatus 100 can keep the
system instant-on function while performing power path management.
More particularly, the charger module 130 can obtain power from the
AC-to-DC adaptor (or the charger) to output the system power signal
at the system terminal SYS of the charger module 130, where the
AC-to-DC adaptor/charger is capable of providing both of the system
and the battery 20 with sufficient power through the charger module
130 at the same time. As a result, the charger module 130 is
capable of charging the battery 20 and powering the system
simultaneously.
It is an advantage of the present invention that the present
invention method and apparatus can prevent unexpected system
voltage drop (or unstable system voltage) when the external power
source mentioned above has a weak charging capability (e.g. in a
situation where the system circuit needs an input current level
that is greater than 500 mA to sustain the system load and the
external power source is a power source that provides insufficient
current, such as a USB-complaint standard downstream port or a USB
OTG device). In addition, the present invention method and
apparatus can meet the USB BC 1.2 standard while performing power
path management when using an AC-to-DC adaptor for single input
battery charger. Additionally, based upon the predetermined
charging profiles respectively shown in FIG. 5 and FIG. 7, the
present invention method and apparatus can prevent the system (e.g.
a chipset) from being damaged by an overshoot waveform of the
voltage level VSYS.
For purposes of distinguishing signal characteristics such as those
respectively shown in FIGS. 5-8, when the voltage of a signal is
kept constant in the beginning of a charging phase such as the
charging phase D, the constant voltage of this signal in this
charging phase can be regarded as the true constant voltage. In
addition, when the voltage of a signal is kept constant in a
non-beginning period of a charging phase such as the charging phase
D, rather than being kept constant in the beginning of this
charging phase, the constant voltage of this signal in this
charging phase can be regarded as the non-true constant
voltage.
Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
* * * * *